<template>
  <label class="el-checkbox" :class="[
    border && checkboxSize ? 'el-checkbox--' + checkboxSize : '',
    { 'is-disabled': isDisabled },
    { 'is-bordered': border },
    { 'is-checked': isChecked }
  ]" :id="id">
    <slot name="csvg" :checked="isChecked"></slot>
    <span class="el-checkbox__input" :class="{
      'is-disabled': isDisabled,
      'is-checked': isChecked,
      'is-indeterminate': indeterminate,
      'is-focus': focus
    }" :tabindex="indeterminate ? 0 : false" :role="indeterminate ? 'checkbox' : false"
      :aria-checked="indeterminate ? 'mixed' : false">
      <span class="el-checkbox__inner"></span>

      <input v-if="trueLabel || falseLabel" class="el-checkbox__original" type="checkbox"
        :aria-hidden="indeterminate ? 'true' : 'false'" :name="name" :disabled="isDisabled" :true-value="trueLabel"
        :false-value="falseLabel" v-model="model" @change="handleChange" @focus="focus = true" @blur="focus = false">
      <input v-else class="el-checkbox__original" type="checkbox" :aria-hidden="indeterminate ? 'true' : 'false'"
        :disabled="isDisabled" :value="label" :name="name" v-model="model" @change="handleChange" @focus="focus = true"
        @blur="focus = false">
    </span>
    <span class="el-checkbox__label" v-if="$slots.default || label">
      <slot></slot>
      <template v-if="!$slots.default">{{ label }}</template>
    </span>
  </label>
</template>
<script>
/* eslint-disable */
import Emitter from 'element-ui/src/mixins/emitter'
import { debounce } from '@/plugin/filter';

export default {
  name: 'ElCheckbox',

  mixins: [Emitter],

  inject: {
    elForm: {
      default: ''
    },
    elFormItem: {
      default: ''
    }
  },

  componentName: 'ElCheckbox',

  data() {
    return {
      selfModel: false,
      focus: false,
      isLimitExceeded: false
    }
  },

  computed: {
    model: {
      get() {
        return this.isGroup
          ? this.store : this.value !== undefined
            ? this.value : this.selfModel
      },

      set(val) {
        if (this.isGroup) {
          this.isLimitExceeded = false;
          (this._checkboxGroup.min !== undefined &&
            val.length < this._checkboxGroup.min &&
            (this.isLimitExceeded = true));

          (this._checkboxGroup.max !== undefined &&
            val.length > this._checkboxGroup.max &&
            (this.isLimitExceeded = true))

          this.isLimitExceeded === false &&
            this.dispatch('ElCheckboxGroup', 'input', [val])
        } else {
          this.$emit('input', val)
          this.selfModel = val
        }
      }
    },

    isChecked() {
      if ({}.toString.call(this.model) === '[object Boolean]') {
        return this.model
      } else if (Array.isArray(this.model)) {
        return this.model.indexOf(this.label) > -1
      } else if (this.model !== null && this.model !== undefined) {
        return this.model === this.trueLabel
      }
      // return false
    },

    isGroup() {
      let parent = this.$parent
      while (parent) {
        if (parent.$options.componentName !== 'ElCheckboxGroup') {
          parent = parent.$parent
        } else {
          this._checkboxGroup = parent // eslint-disable-line
          return true
        }
      }
      return false
    },

    store() {
      return this._checkboxGroup ? this._checkboxGroup.value : this.value
    },

    /* used to make the isDisabled judgment under max/min props */
    // isLimitDisabled() {
    //   const { max, min } = this._checkboxGroup
    //   return !!(max || min) && (this.model.length >= max && !this.isChecked) || (this.model.length <= min && this.isChecked)
    // },

    isDisabled() {
      return this.isGroup
        ? this._checkboxGroup.disabled || this.disabled || (this.elForm || {}).disabled || this.isLimitDisabled
        : this.disabled || (this.elForm || {}).disabled
    },

    _elFormItemSize() {
      return (this.elFormItem || {}).elFormItemSize
    },

    checkboxSize() {
      const temCheckboxSize = this.size || this._elFormItemSize || (this.$ELEMENT || {}).size
      return this.isGroup
        ? this._checkboxGroup.checkboxGroupSize || temCheckboxSize
        : temCheckboxSize
    }
  },

  props: {
    value: {},
    label: {},
    indeterminate: Boolean,
    disabled: Boolean,
    checked: Boolean,
    name: String,
    trueLabel: [String, Number],
    falseLabel: [String, Number],
    id: String, /* 当indeterminate为真时，为controls提供相关连的checkbox的id，表明元素间的控制关系 */
    controls: String, /* 当indeterminate为真时，为controls提供相关连的checkbox的id，表明元素间的控制关系 */
    border: Boolean,
    size: String
  },

  methods: {
    addToStore() {
      if (
        Array.isArray(this.model) &&
        this.model.indexOf(this.label) === -1
      ) {
        this.model.push(this.label)
      } else {
        this.model = this.trueLabel || true
      }
    },

    handleChange: debounce(function (ev) {
      if (this.isLimitExceeded) return
      let value
      if (ev.target.checked) {
        value = this.trueLabel === undefined ? true : this.trueLabel
      } else {
        value = this.falseLabel === undefined ? false : this.falseLabel
      }
      this.$emit('change', value, ev)
      this.$nextTick(() => {
        if (this.isGroup) {
          this.dispatch('ElCheckboxGroup', 'change', [this._checkboxGroup.value])
        }
      })
    }, 100, true)
  },

  created() {
    this.checked && this.addToStore()
  },
  mounted() { // 为indeterminate元素 添加aria-controls 属性
    if (this.indeterminate) {
      this.$el.setAttribute('aria-controls', this.controls)
    }
  },

  watch: {
    value(value) {
      this.dispatch('ElFormItem', 'el.form.change', value)
    }
  }
}
</script>
